November 5, 2013

1. November 5, 2013 HW – TEST Tomorrow! Scientist Biography due 11/12 Do Now – It’s Election Day. Vote for your favorite element Today I Will… Challenge my knowledge of chemical equations and interactions in a review game of eggspert!

2. Are you an Eggspert??? Test #2 review

3. The Rules… • Only one person from each group comes up to your team’s egg with one hand behind back. • We will rotate so everyone gets a turn. • Only that person is able to give the answer – no help from teammates or point taken away. • No slamming, moving or hitting the eggs. • I will read the question then release the eggs.

4. Identify the coefficient in: 2CHCl3 2

5. In chemical reactions, what does the principle of conservation of mass mean? a. Matter is not created or destroyed. b. The total mass of the reactants is greater than the total mass of the products. c. The total mass of the reactants is less than the total mass of the products. • Matter is not changed. a. Matter is not created or destroyed.

6. Physical or Chemical Change? Chemical

7. How do you count atoms? Coefficient x subscript = # of atoms

8. What is a compound? • Pure substance composed of two or more different elements joined by chemical bonds.

9. A chemical equation shows • Elements and mixtures • Hydrogen and Oxygen • Reactants and Products • Chemical bonds c) Reactants and products

10. Identify the subscript in: 2CHCl3 3

11. Physical or Chemical Change? Chemical

12. True/False In an exothermic reaction, heat is released. True

13. Name one evidence/observation for chemical reactions

14. Identify the reactant(s) in:2Mg + O2 2MgO 2Mg + O2

15. What is a subscript? • Shows the number of atoms of an element in a molecule or the ration of elements in a compound • The number AFTER the element.

16. Name one evidence/observation for chemical reactions

17. What is a chemical equation? • A shorter, easier way to show chemical reactions using symbols instead of words.

18. Explain: all compounds are molecules but not all molecules are compounds. A molecule is formed when two or more atoms join together chemically. A compound is a molecule that contains two or more different elements. Molecule & Compound = H2, O2, H2O Compound = H2O

19. What is this a graph of? • Exothermic Reaction

20. What is a molecule? • A particle made of two or more atoms held together by chemical bonds.

21. Identify the product(s) in:2Mg + O2 2MgO 2MgO

22. What is the Law of Conservation of Mass? • Matter is not created or destroyed • The total mass of the reactants is equal to the total mass of the products. • Atoms are rearranged (no loss or gain)

23. The rate of a chemical reaction can be increased by all of the following except: a)increasing temperature b) increasing concentration c) decreasing concentration d) increasing surface area c) decreasing concentration

24. Fill in the blank • A chemical reaction that releases energy in the form of heat is a(n) ____________________ reaction. exothermic

25. Name one evidence/observation for chemical reactions

26. True/False Endothermic reactions feel cold. True

27. Which of the following is a balanced chemical equation? a. H2O2H2O + O2 b. 2 Fe2O3 + 3 C 4 Fe + 3 CO2 c. SO2 + O2 + 2 H2O 4 H2SO4 • 2 Mg + HC1 MgCl2 + H2 2 Fe2O3 + 3 C 4 Fe + 3 CO2

28. Fill in the blank • Bonds that form between two nonmetal atoms usually are ____________________ bonds. covalent

29. True/False An inhibitor decreases the rate of a reaction. True

30. The force that holds atoms together is called • a. a chemical bond. • b. conservation of matter. • c. heat. • d. a chemical change a) a chemical bond.

31. What is this a graph of? Endothermic Reaction

32. True/False • When an atom gains an electron it becomes a positive ion. False

33. Fill in the blank • Bonds that form between a metal and a nonmetal atoms usually are ____________________ bonds. ionic

34. A material used to decrease the rate of a chemical reaction is a(n) • a. inhibitor. • b. catalyst. • c. enzyme. • d. fuel. a. inhibitor.

35. In an equation, numbers often appear in front of a chemical formula. These numbers tell you the a. number of atoms in each molecule in the reaction b. number of elements in the reaction. c.number of molecules or atoms of each substance in the reaction. d.numberof molecules in each atom in the reaction. c. number of molecules or atoms of each substance in the reaction.

36. Fill in the blank A subscript shows the number of ____________________ of an element in a molecule. atoms

37. chemical bond formed when two atoms share electrons is called a(n) • a. ionic bond. • b. covalent bond. • c. polyatomic bond. • d. crystal bond. b. covalent bond

38. True/False • Chemical reactions that absorb energy are said to be exothermic. False

39. Fill in the blank • Two or more atoms may combine to form a ____________________. molecule

40. Name one of the three ways to affect the rate of chemical reactions • Concentration • Surface Area • Temperature

41. Make a molecule out of the following atoms. Determine if it is an Ionic or Covalent Bond. H H H N

42. Make a molecule out of the following atoms. Determine if it is an Ionic or Covalent Bond. H H H Covalent N

43. Make a molecule out of the following atoms. Write the chemical formula for the molecule. H H H N

44. Make a molecule out of the following atoms. Write the chemical formula for the molecule. H H H N NH3